A study on the electrophoretic deposition of 3YSZ coating on AZ91 alloy plated by Ni-P electroless interlayer

The Zirconia stabilized by 3wt% yttria (3YSZ) on AZ91 was applied by Electrophoretic Deposition (EPD). In order to improve of adherence, compression and corrosion resistance of the coating, an Ni-P electroless interlayer was prepared between substrate and top coat. Finally, A heat treatment was done on top coat with Ni-P interlayer. The results indicate that Ni-P interlayer not only has favorable effect on adherence and compassion of zirconia coating on AZ91, but also significantly improves the corrosion resistance. Also, scanning electron microscope (SEM) was used in order to investigation of morphology, adherence and compression of coating, in addition X-ray diffraction (XRD) was used for phase analyze. The corrosion resistance was investigated by electrochemical impedance spectroscopy (EIS) in 3.5wt% NaCl solution.